For detecting consumption data, counting devices or mechanical counting units are known that are constructed to detect a volume flow of a fluid. These mechanical counting units are constructed in such a way that, by means of the volume flow, for the most part one counting wheel is driven directly or indirectly, which transfers each rotation to a counting unit. For a known cross section of the volume flow, an exact, defined volume can be allocated to each rotation. In this way, the volume flow can be detected with the counting unit. Such mechanical volume flow counters usually do not provide a connection to other devices and must be read “by hand.” Remote electronic querying or similar functions thus are not to be realized. An advantage of these devices is high operating reliability since these devices exhibit high stability under loading and have a long service life and are independent of auxiliary energy sources, such as, for example, electrical energy. However, one disadvantage is that the data detected by the device can only be read manually and only on site directly from the device.
It is further generally known to detect a volume flow on the basis of a magnetically inductive flow-rate measurement. Here, under the use of Faraday's Law of Induction, an electrical voltage is induced. This voltage is a measure of the volume flow for a known cross section of a flowing fluid. This measurement principle uses the separation of moving charge in a magnetic field. The fluid to be measured flows through a tube made from non-magnetic material with an electrically insulating lining. Charge carriers contained in the fluid are deflected by a magnetic field that is perpendicular to the direction of flow. High-impedance electromotive forces, which generate electrical voltages in the millivolt range on electrodes made from corrosion-resistant material and mounted in the tube, are created by the charge separation. A disadvantage of this measurement principle is the limitation of applicability just to electrically conductive fluids. For gases, the method is based on the lack of electrical conductivity. Thus, this method cannot be applied to all fluids.
It is further generally known to perform a flow-rate measurement and thus a detection of the volume flow according to the so-called differential-pressure method. Here, the kinetic energy of a fluid is converted into potential energy, which can be measured as a pressure. A diaphragm, provided as a perforated disk for reducing the flow cross section forces the flowing fluid to increase its velocity. The kinetic energy is increased. In this way, according to the law of conservation of energy, the pressure of the fluid after the diaphragm is smaller. The potential energy of the fluid decreases. This pressure difference is measured with a sensor and converted in an evaluation device into the volume flow. A disadvantage here is that such measurement arrangements require an external energy supply. This is formed either by an electrochemical energy storage device, for example, an accumulator, or by a power supply. Such dependence leads to high maintenance expense or installation expense, because a necessary power supply is to be installed up to the relevant counter, or the electrochemical energy storage device, for example, the battery, must be replaced at regular time intervals. In particular, in connection with an electrochemical energy storage device, a reliable and steady energy supply is also not ensured, so that in times without an electrical supply of energy, no measurement or no volume-flow detection can take place. Also, a power supply-dependent energy detection or energy supply is not, in principle, free of interruptions, so that here lack of volume-flow detection is also possible at times of energy interruption.
The document US 2003/125600 A1 discloses a moving system which is suitable to keep itself in a rectilinear movement. The electrical energy generated by the system disclosed in US 2003/125600 A1 is utilized to self-excite the oscillation in the spring, wherein that oscillation is essential for the system to move. Even though US 2003/125600 A1 discloses in FIG. 4 and FIGS. 5A to 5D an energy converter with a first element and a second element wherein the first element is coupled mechanically to the second element by means of a coupling element and wherein the coupling element is constructed to store mechanical energy and to output stored mechanical energy and wherein the first element receives a movement of a medium, and transmits the movement to the coupling element, and wherein a means is provided, which prevents, with a predetermined retaining force, a transmission of the movement to the second element until the retaining force is exceeded, the converted electrical energy couldn't be applied to be transmitted to a radio transmitting device or a radio transmitting and receiving device.